- Jan 29, 2022
The 820QM firmware will solve his issues with nothing else being done except fixing the NT Code error.I have done this already myself,and all works except wifi calling of course.Try this:
1. Create a new folder in your internal storage named "enable_ue"
2. Dial #546368#*820
3. Go into field test==>universal enabler
4. Click "Create New Config"
5. Then enable all 4 boxes and see if VoLTE will work
If this doesn't work then flashing Open US G820QM firmware is the only solution for you to get T-Mobile VoLTE support.
Saw your reddit post, for the Mint APN leave the MNC as 240, Mint sim cards are MCC 310 MNC 240, not 310 260 like actual T-Mobile sim cards. This is why it disappears when you try to save it with the MNC as 260.